You may have learned in school that every living thing is made up of cells. House plants, giraffes, nudibranchs, even human beings—we’re all alive thanks to these tiny building blocks of life.
They may be small, but cells are made up of even tinier structures. Today, we’ll learn about a very important part of the cell. It’s the semipermeable membrane!
What is a semipermeable membrane? It’s the outer layer that protects the cell. “Semipermeable” means that it lets some molecules enter or exit the cell and blocks others.
Have you ever been to a concert or big sports event? If so, someone probably checked your ticket before you were able to enter. If you show up without a ticket, they won’t let you in. The membrane does a similar job. It controls what comes into the cell. It can also limit how much of a substance enters.
What about larger molecules? They rely on transport proteins. The cell’s genetic code decides what can and cannot pass through the membrane. Transport proteins move the allowed molecules across the membrane and into the cell.
When water molecules enter a cell, it’s called osmosis. This process plays an important part in helping keep your cells healthy. Osmosis and the cell membrane help living things maintain homeostasis. This is a state of equilibrium at which life processes can be carried out.
This is just one of many processes happening in your body every day. Your cells grow, duplicate, and carry out their jobs, all without you realizing it! Life really does depend on these tiny, hard-working structures.
Read more at Wodnerpolis.org